Method for Introducing Detergents and Associated Washing Machine

ABSTRACT

A method and washing machine that drives a cylindrical drum body, having openings and rotatably supported about an approximately horizontal axis in a tub, in a preferred direction of rotation, and that flows a detergent-liquid mixture in a stream onto an area of an upper quandrant of the cylindrical drum at an oblique angle against the preferred direction of rotation.

The starting point of the present invention is a method for theintroduction of detergents into program-controlled washing machines by adetergent-liquid mixture flowing through a preferably cylindrical drumbody in which openings are provided of a washing drum supportedrotatably around an at least approximately horizontal axis in a tub.

Such a method follows on from DE 43 42 627 C2 or DE 43 42 626 C2. It isable to be executed with a washing machine which features a detergentdispensing facility controllable in respect of detergent temporarilystored within it and a detergent feed line as well as a drive motor forthe washing drum controllable in respect of its direction of rotation.The term detergent is used here and below as a simple generic term forall types of washing, fabric care and rinsing agents which are normallyused in washing machines.

With washing machines of the type discussed here the detergent requiredfor a washing program is deposited in a drawer of the detergentdispensing facility. To accept different types and quantities ofdetergents there are generally a number of compartments present in thedrawer, which are flushed through during the individual washing programphases by means of a controllable water jet. The water-detergent mixtureflows via a dispensing line into the tub. After the washing process thewashing liquor is pumped away. To this end an outlet opening is providedat a fixed point in the tub with a flange for connecting the drain pumpline.

Manufacturers of washing machines are making efforts to use thedetergents employed in the washing process as effectively as possibleand to avoid wastage. Wastage can arise for example by undissolveddetergent getting into the drain pump line at the tub, no longer beingdissolved and thus remaining ineffective for the washing process.

To counter such detergent wastage, recirculating pump systems are usedin known washing machines for recirculating detergents back into the tub(e.g. DE 37 04 079 A1 and DE 35 40 741 A1). Using a recirculating pumpthe washing liquor is pumped away via the drain pipe from the lowestpoint of the tub and transported to the upper area of the tub. Thewashing liquor is thus circulated; the detergent is dissolved byconstantly being moved in the liquor.

Another approach to countering detergent wastage consists of radicallyreducing the volume of liquor ineffective for the washing process. Invarious embodiments solutions are proposed for closing off the drainpipe to the liquor or circulation pump during the washing process. Theclosure mechanism prevents undissolved detergent being able to bedeposited in the outlet flange and thus being lost to the washingprocess.

DE 100 65 404 A1 is given as an example of such a solution. In thispatent it is proposed that the opening to the drain pipe be closed offby a float which is pressed against an annular projection in the drainopening of the tub. To improve the sealing effect the float is coatedwith rubber or with an elastic plastic. The pressure on the float iscreated by the column of water standing in the feed line to the returncontainer. Arranged in the upper area of washing machine is a returncontainer in which a column of water stands above the level of thefreshly supplied detergent-water mixture and thus has the heightnecessary for creating the pressure acting on the float. The used liquoris pumped out of the tub via the return container.

The disadvantage shared by the two solutions described above is that thewashing machines have to be equipped with expensive additional devicesin order avoid or reduce detergent wastage. These additional devices addnot inconsiderable costs to such washing machines. A furtherdisadvantage of the circulation pump system described in the firstinstance is that additional energy has to be used during operation ofthe washing machine.

The object of the invention, to minimize detergent wastage, is tospecify a method that can be implemented with a very small materialoutlay and which requires no additional energy to be expended inoperating the washing machine.

Inventively the object is achieved by the features given in thecharacterizing part of claim 1. In addition a washing machine achievingthis object for executing the method is specified in claim 6. Furtheradvantageous embodiments of the invention are contained in the subclaimsof which the features can be applied individually or in any givencombination with each other or with the features of claim 1 or 6.

According to the invention, while the washing drum is being driven in apreferred direction of rotation, the detergent-liquid mixture flows in astream against the moving drum body so that the stream hits an area ofthe drum body at an oblique angle, said area lying in the upper quadrantof the cylinder form of the drum. The drum is moved against thedirection of flow of the introduced detergent-liquid mixture in apreferred direction of rotation. In addition there is a preferredvariant in which the detergent-liquid mixture flowing downwards is keptaway from the drain opening for as long as possible.

It is now evident that by this simple measure the dissolving of thedetergent can be significantly improved without additional effort. Anespecially good effect can be achieved with the method if the surface ofthe washing drum is a surface which amplifies an eddy movement,especially a structured body surface. This enables the detergent-liquidmixture to be retained for a long time in the upper area as the drumrotates, i.e. away from the drain opening.

The method can be implemented with the minimum effort since it isessentially characterized by a pure software solution. No additionalmodules or parts to be fitted are necessary for practical implementationof the method. The method can be used for washing machines in which thedetergent-liquid mixture is not directed centrally from above onto thedrum body and can be retrofitted by reprogramming or replacing theprogram chip.

In an embodiment of the invention the detergent-liquid mixture flowsover almost the entire depth of the drum distributed onto the drum body.The inflowing liquid flows more evenly over the drum body, promoting thedissolving of the detergent. The even distribution also has the effectof enabling more mixture to reach the inside of the drum through theopenings in the drum body even during initial feeding. The washing isthus wetted more quickly. The wetting of the washing can be furtherimproved by the openings in the drum body having a greater admittancecapability in the preferred direction of rotation.

The amount of liquid hitting the washing via the openings in the drumbody during the feeding phase is—within limits—able to be controlled byregulating the speed of rotation of the drum. The method in accordancewith the invention thus offers an additional option for designing thewashing programs.

The inventive method and its associated exemplary embodiments aredescribed with reference to drawings listed below. The figures show

FIG. 1 a washing machine in a perspective view and

FIG. 2 a detailed view of the upper area of the drum body.

FIG. 1 shows a perspective view of a washing machine 1 from the front.To simplify the diagram it contains only the components of significancefor the function of the inventive method.

The tub 3 and the washing drum 4 able to be rotated therein around ahorizontal axis 14 have a loading opening which can be closed by meansof a door which has been removed in this diagram. Arranged in the upperhousing area are the control panel 1 and also the detergent dispensingfacility. The detergent required is deposited in its drawer 2 which canbe pulled out horizontally in a forwards direction. To accept differentdetergents the drawer 2 is subdivided into a number of compartmentswhich can be flushed out under program control using fresh water fedfrom an external water supply system.

The floor of the dispensing facility merges with an outlet flange forthe detergent feed line 7. In the drawing the direction of flow of thedetergent-liquid mixture is indicated by arrows 6. To pump out thewashing water a drain opening 10 is provided at the lowest point of thetub 3, which is linked to the drain pump 11 via a connected line.

The detergent-liquid mixture is introduced distributed over the width ofthe drum body 13 (FIG. 2) via a liquid distributor 5 which is attachedin parallel to the axis of rotation of the drum 14 centrally to theoutside of the tub 3 and has a series of through openings. At its twoedges towards the rear panel and towards the front panel the drumsurface 13 features raised edge bars resulting from manufacturing (notshown) which prevent the incoming detergent-liquid mixture from flowingaway over the sides. The stream of liquid 12 hits the drum body 13 ofthe washing drum 4 from above at an oblique angle. The movement of thedrum body 13, as a result of the preferred direction of rotation 8 ofthe washing drum 4 is directed against the direction of flow 12 of theincoming detergent-liquid mixture. The detergent-liquid mixture isintroduced into an area of the tub within the upper quadrant of the drumcylinder.

This constructive measure and the flow caused by the rotation of thedrum against the direction of movement of the drum body and the factthat the mixture is kept away from the drain opening helps the detergentto dissolve.

In the exemplary embodiment the throughflow openings 9 in the drum body13 are embodied by gill-like raised sections in the form of a half cone(see FIG. 2). This form on the one hand causes a delay in the drainingof the detergent-liquid mixture from the drum body 13. On the other handthe openings 9 made in the direction of rotation 8 of the drum 4 causeliquid to be directed into the inside of the drum to an increasedextent. The wetting-through of the washing is speeded up. Other, ifnecessary additional raised structures in the drum surface 13,preferably those which cause a greatly eddied flow of thedetergent-liquid mixture, can support the length of time for which themixture remains on the drum surface 13 and its entry into the washingdrum 4 and contribute to the detergent being well dissolved at thecorrect time, before the mixture reaches the floor of the tub and thedrain opening.

1-8. (canceled)
 9. A method for introducing detergents inprogram-controlled washing machines, the method comprising: driving acylindrical drum body, having openings and rotatably supported about anapproximately horizontal axis in a tub, in a preferred direction ofrotation; and flowing a detergent-liquid mixture in a stream onto anarea of an upper quandrant of the cylindrical drum at an oblique angleagainst the preferred direction of rotation.
 10. The method of claim 9,wherein the preferred direction of rotation results in thedetergent-liquid mixture falling downwards in a flow pointing away froma drain opening in the tub.
 11. The method of claim 9, wherein thepreferred direction of rotation results in the detergent-liquid mixtureentering more quickly through the openings in the drum body or isexpelled through the openings more effectively than in an oppositedirection of rotation to the preferred direction.
 12. The method ofclaim 9, wherein the flowing comprises distributing the flowing over thewidth of the drum body into the tub according to the depth of thewashing drum.
 13. The method of claim 9, wherein driving the cylindricaldrum body comprises controlling a speed of rotation of the drum body.14. A washing machine comprising: a detergent dispenser controllable fortemporarily storing an output of detergent; a detergent feed lineextending from an area of a tub and for directing a stream ofdetergent-liquid mixture falling from a mouth of the detergent feed lineonto a surface of a washing drum from above at an oblique angle; and adrive motor for controlling a direction of rotation of the washing drumand for rotating the washing drum in a preferred direction of rotationagainst the stream.
 15. The washing machine of claim 14, wherein thewashing drum comprises openings in a drum surface which in each casehave an admittance or an expulsion effect which are greater on rotationof the washing drum in the preferred direction of rotation than they areduring rotation in the direction opposite to the preferred direction ofrotation.
 16. The washing machine of claim 14, wherein the drum surfacecomprises structures which delay an unhindered draining of thedetergent-liquid mixture.